Piston for rock drills



E. B. LEAR PISTON FOR ROCK DRILLS Filed OC'C. 8,- 1928 Dec. 8, 1931.

HIS ATTORNEY Patented Dec. 8, 1931 EARL B. LEAR, 'or'.rnrttrrsiarme, NEW .TRsEYAs sIGNoR 'rOVINeEnsoLL-nnlm) CoM-f PANY, or JERSEY airfare-aw' .TEiisEmaeoRroR-Ariou or NEW JERSEY E .rrs'roivrortnocxnmtrisl' 'e Application mea octopus, 192s. serial No. 311,104.

This invention relatesto rock drills, but more particularlyto 'pistons for rock drills. One Yobject of this invention is to enable the operation of'a rock-drill VWith a' Water tube and with or 1 ivithoutf-anair tube `Without. changing the piston. Other objects Will be in part obvious and-in part pointedouthere-l inafter.- I .i f Y, 4One :embodiment of the invention is dis# closed in the accompanying drawings, in Which Figure 1 is a. longitudinal view of ia rock drill., partly insection, shov'ving boththe air tube and the Water tube inplace v4 Figui-e2 is aview similar to Figurefl, but showing the interior ofthe; drill with the air tube removed. j ,j p Referring more. particularly to theV dravv-A ings, designates arock drillhaving a cyl-l inder l2 and a piston Treciprocably mounted therein -and adapted toV strike against the shank end of a drill steel 32. lAs is customary, the .drill steelv 32 ish-o lloW, being provided with a ycentral-bore l'100 to receive a Water tube 7 8 extending through-abore 40 'in the pistoncoaxialwith the lpiston. VThe bore 40 issuiiiciently.large-to receivealso an air ktubeg102 having 4a sliding t in the `bore 40 sons to prevent :an excessive quantity of air from passing from the cylinder-12through the bore 40. f Inv this type-ot` tool the tube 7 8 is connected with a source of supply of cleansing WaterV under pressure which is Vmixed with air under full line pressure supply 4through the tube 102 which airlsupplies `the force for driving the. cuttings `from the lhole be-ing drilled. 1

. `In Imany cases itis desirable, hoWever, t-o omit the air supply tube 102 and .usually this cannot be done'unless the piston 22 AAis re placed With one ofa smaller bore closely {ittingf the Water tube 78.- This inventionprovides means for lpermitting the same pistonto be used under either condition. To this end thepiston is provided witha tapered counterbore 42,150 receive .a plug 104 adapted; to :be driven `into thebore 42. Preferably the bore 42 is of-*somewhat greaterlength thanthe plug 104 and :said plug is spacedfrom'the smaller -end of vthe bore to permit compensation Vfor `Wear on the plug andthe"v Walls `of the bore. lThe plug 104 `is provided with a bore 106 of approximately the vdia-meter ofv the tube 78 so as toiprevent leakage ofairj between the tube and the plug.- When itis desired to use the air tube 581m addition to the'ivater `tube 78Tthe plug 104is driven out and the piston is inireadinessto receive both tubes58and78.-

Inthis instance the rockdrill is of stand-` ardiconstruction' having a ronthead 416 and -a front cylindervvasher 18interposed between' the .iront headandl the cylinder.- A bore 20 inthefront cylinder .Washer acts asa guide and centralizer `:tor areduced forward' extension 22on the whicheisshown. e Ribs l24-on the piston extension22 4cooperate with iiutes `in a chucknut 26 which is -ixedin achuck 28 byvmeansof screw threads .30. These elements form part ofthemeans for rotating a drill steel 32 and need not be described in greater idetail since they r-orm no partgof' this invention. The ratchet and pa'vvl mechanism of the device pisssh'oWn in part at 34. w

:A longi'iudinal` central boref36 `in `the `piston 14 accommodatesfa rie bari-i8` Whichi-is only show .nin part but'whichfextends a substantial distance `into the piston vwhen zthe piston` Vis-in its rearvvardmostv position. A smaller cylindrical bore 40 is formed in Athe forward end-ofthe piston extension 22 and a tapered b'ore f42 islformed between the Vbore 36 and-thefbore40. i'

A vback head `44 is securedato the @cylinder 12 in a manner Wellknovvn inthe art. -A

Vthrottle valve -46 having a handle 48admits piston 14, only `a part of.

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air tube 58. The plug 66 has a circun'lferential groove 68 from which radial passages 70 lead to a central aperture 72. A short passage 74 connects the chamber 50 t-o the groove 68. A packing member 76 through which eX- tends the water tube 78 is placed on the plug 66 in the bore 64. A flange 80 on the water tube 78 rests on the packing member 76. A passage 82 leads from a chamber 84 in the back head 44 to a chamber 86 in which the water tube flange rests. In order to secure the water tube 78, the packing member 76, the plug 66 and the air tube 58 .firmly in place, a threaded plug 88 is screwed into a-threaded aperture 90 in the back head and against the water tube flange 80. The plug 88 is provided with a hole 92 which receives the end of the water tube` 78. A passage 94 leads from the hole 92 to the chamber 86 and a packing washer 96 is placed under the head 98 of the plug 88.

The operat-ion of the tool as shown in Figure 1 and described above is as follows:

Assuming therock drill to be in operation,

water under pressure in the hose 54 enters thev chamber 86 by way of the passage 82, it then entersthe water tube 78 by way of the passage 94 and the hole 92. The water passes through the water tube and through a bore 100 in the drill steel 32, to the drill hole (not shown) where it cleanses the drill hole of rock particles. An additional cleansing and blowing effect is obtained by pressure fluid which passes from the chamber 50, through the passages 74 and 70 into a passage 102 between the exterior wall of the water tube 78 and the interior wall of the air tube 58. Frein the forward end of the air tube the pressure fluid passes into the drill steel bore 100 and assists the water in cleansing the hole being drilled.

`As above referred to, under certain drilling conditions it is undesirable that pressure fluid be'used as a cleansing medium and in cases of' this kind it is an advantage to be able to rem-ove the air tube and operate with water as the only means of removing the rock particles from the drill hole. VWhen these conditions arise it is a simple matter to adapt a tool embodying this invention to the requirements above mentioned. The piston 14 i-s first removed from the cylinder and the tapered plug 104 driven into the tapered seatg42. The plug 88 is removed and the water tube 78, packing member 76, plug 66 and air tube 58 removed. The plug 66 is replaced by a plug 108 having a central bore 110. The packing member 76 is replaced, the piston returned to the cylinder and the water ltube `v78V inserted through the packing member 76, the bore 108 in the plug 110, through the bore 106 in the plug 104 and into thehollow drill steel 32.

The plug 104 effectually seals the interior of the piston against entry of water and also acts as a guide and centrulizer for the water tube. The plug 104 remains tightly seated due to the fact that each downward blow of the piston caused it to tend to seat more tightly. It is however, easily removed by possible for pressure fluid to leak into parts f,

of the drill where it is not desired.

I claim:

1. In a fluid actuated rock drill, the combination of a cylinder with a back head, a piston in the cylinder having a longitudinal bore therethrough, a recess in the back head coaxial with said bore, a passage in said back head for supplying pressure fluid to the recess, a water tube extending through the recess and the bore, removable means in the back head encircling the tube and seated in the recess to prevent entrance of pressure fluid into said recess, and removable means in the forward end of the piston encircling the tube and seated in the bore to prevent entrance of water into said bore.

2. In a fluid actuated rock drill, the combination of a cylinderI with a back head, a piston in the cylinder having a longitudinal bore'therethrough, a recess in the back head coaxial with said bore, a passage lin said back head for supplying pressure fluid to the recess, a water tube extending through the recess and the bore, a plug in the back head encircling the tube and seated in the recess to prevent entrance of pressure fluid into said recess, and removable means in the forward end of the iston encircling the tube and seated in the ore to prevent entrance of water into said bore. Y

3. In a fluid actuated rock drill, the combination of a cylinder with a back head, a piston in the cylinder having a longitudinal bore therethrough, a recess in the back head coaxial with saidrbore, a passage in said back head for supplying pressure fluid to the recess, a water tube extending through the recess and the bore, removable means in the back head encircling the tube and seated in the recess to prevent the entrance of pressure fluid into said recess, and a tapered plug in the forward end of the piston encircling the tube and seated in the bore to prevent entrance of water into said bore.

4. In a fluid actuated rock drill, the combination of a cylinder with a back head, a piston in the cylinder having a longitudinal bore therethrough, a recess in the back head coaxial with said bore, a passage in said back head for supplying pressure fluid to the recess, a water tube `extending through the recess and the bore, a plug in the back head encircling the tube and seated in the recess to prevent entrance of pressure fluid into said recess, and a tapered plugin the forward end of the piston encircling the tube and seated in the bore to p-revent entrance of water into said bore; v

5. In a fluid actuated rock drill, the combination of a cylinder with a back head, a piston in the cylinder having a longitudinal bore therethrough, a tapered portion at the forward end of the bore, a recess in the back head coaxial with said bore, a passage in the back head for supplying pressure fluid to the recess, a water tube extendingV through the recess and the bore, aflange on the water tube adjacent the recess, a member threadedly en- V i gaging the back head and seated against one side of the flange, a plug in the back head env circling the tube and seated in the recess to prevent entrance of pressure fluid into said recess, a packing memberv between the plug and the flange on the water tube, said packing member and plug being secured in position by the pressure of the threaded member against the lia-nge, and a tapered plug engaging the tapered portion of the piston bore and encircling the tube to prevent entrance of water into the bore, said tapered plug being constantly urged into closer engagement with the piston upon forward movement thereof. In testimony whereof I have signed this specification. v j

EARL B. LEAR. 

